@Article{bouyarmane:tac:2018,
  author    = {Bouyarmane, Karim and Kheddar, Abderrahmane},
  title     = {On Weight-Prioritized Multi-Task Control of Humanoid Robots},
  journal   = {IEEE Transactions on Automatic Control},
  year      = {2018},
  volume    = {63},
  number    = {6},
  pages     = {1632--1647},
  month     = {June},
  doi       = {10.1109/TAC.2017.2752085},
  url       = {https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=\&arnumber=8036254},
  keywords  = {Lyapunov\textquotesingle s indirect method, multiobjective optimization, multitask control, quadratic-program (QP) stability},
  abstract  = {We propose a formal analysis with some theoretical properties of weight-prioritized multi-task inverse-dynamics-like control of humanoid robots, being a case of redundant " ma-nipulators " with a non-actuated free-floating base and multiple unilateral frictional contacts with the environment. The controller builds on a weighted sum scalarization of a multiobjective optimization problem under equality and inequality constraints, which appears as a straightforward solution to account for state and control input viability constraints characteristic of humanoid robots that were usually absent from early existing pseudo-inverse and null-space projection-based prioritized multi-task approaches. We argue that our formulation is indeed well founded and justified from a theoretical standpoint, and we propose an analysis of some stability properties of the approach: Lyapunov stability is demonstrated for the closed-loop dynamical system that we analytically derive in the unconstrained multiob-jective optimization case. Stability in terms of solution existence, uniqueness, continuity, and robustness to perturbations, is then formally demonstrated for the constrained quadratic program.},
  publisher = {IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC},
  address   = {445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA}
}